Piezoceramic composition is used as a piezoelectric element in the making of actuators, ultrasonic sensors, ultrasonic transducers or the like. Since piezoceramic composition has excellent piezoelectric property, lead zirconate titanate (PZT) or the like containing a lead compound has already been practically used. However, due to a concern that such piezoceramic composition containing a lead compound may negatively affect the environment, a lead-free piezoceramic composition is now attracting attention and is being researched and developed. The alkaline niobate-piezoceramic composition, as disclosed in Patent References 1 to 3 below, is such a piezoceramic composition free of a lead compound.
The piezoceramic composition as disclosed in Patent Documents 1 to 3 is a perovskite compound signified as composition formula ABO3 that contains potassium and sodium as elements of Site A and contains niobium and tantalum as elements of Site B.